Method for determining the position of a tool of a rock drill

ABSTRACT

A method for determining the position of a feed beam (3a to 3c) of a rock drilling equipment so that first, the position of a base (1) of the rock drilling equipment relative to rock is determined in the general system of coordination and after that, the position of the feed beam (3a to 3c) relative to the base (1) is measured. Measuring devices (6a to 6c) fixedly mounted in the base (1) at a distance from one another and at least two measuring devices (9a to 9c, 10a to 10c) attached to the feed beam at a distance from one another at a predetermined position are used in the method, whereby at least some of the measuring devices comprise a transmitter and at least some a receiver, respectively. The position of the feed beam (3a to 3c) relative to the base is measured, for example, by using the propagation time of the oscillation energy transmitted by each transmitter to various receivers and by calculating on the basis of this the position of the measuring devices (9a to 9c, 10a to 10c) of the feed beam relative to the measuring devices (6a to 6c) mounted in the base (1) and based on this, by calculating the position of the feed beam relative to the base (1) and thus relative to the general coordination of the rock.

BACKGROUND AND SUMMARY OF THE INVENTION

The invention relates to a method for determining the position of a toolof a rock drill in a known system of coordination relative to rock whenusing a rock drilling equipment comprising a base, at least one drillingboom mounted pivotally relative to the base and a rock drill connectedpivotally relative to the boom to the other end of the boom and providedwith a tool, in which method the position of the base of the rockdrilling equipment in said system of coordination is determined and theposition of the tool in said system of coordination is determined on thebasis of the position of the base.

In excavating underground spaces, the accuracy of excavation is highlysignificant--the space to be excavated, e.g. a traffic tunnel, has beenset a nominal measure which must not be reduced. When using thedrilling/explosion method, drilling accuracy has a significant effect onthe accuracy of excavation. In order to improve the drilling accuracy ofholes, the positions of planned holes can be measured in advance withseparate measuring devices and marked on the rock surface. Anothermethod is to use instrumented or automatic drilling equipments in whichthe drilling boom is provided with sensors measuring the position of itsjoints; on the basis of the sensors the position and direction of therock drill and thus of its tool relative to the base of the equipmentcan be determined--when this information is connected to a separatelydetermined position and direction of the base of the equipment, theposition and direction of the drill relative to the planned drillpattern can be determined and thus controlled. Regardless of the use ofdifferent methods, drilling accuracy has in practice been variable. Thisis because the methods require either handiwork or skill or that themeasuring of the position of the joints of the drilling boom aresensitive to e.g. variation in the mechanical characteristics of theparts of the boom caused by wear and exterior forces acting on the boom.The variation in drilling accuracy leads, for example, to that inpractice, more rock has to be excavated as a precaution than wasplanned. This causes additional costs in drilling, in explosion, inhandling the blasted rock and in supporting the space. The variation indrilling accuracy is also harmful when excavating ores in which case theexcavation of extra rock only incurs costs. Also, the precise directionand positioning of a tool is difficult in other rock drilling activity,such as when extracting off rock blocks with a percussion hammer bymeans of a striking tool or when doing any essential work with varyingrock drilling equipments.

Finnish Patent Application 884,970 discloses an arrangement in which afeed beam of a rock drilling equipment is directed by using at leastthree laser beams the direction and position of which relative to thegeneral system of coordination is known and by placingtransmitters/receivers at each beam and at the feed beam at a distancefrom one another so that the direction and position of the feed beam inthe general system of coordination of the tunnel can be measured on thebasis of the oscilllation waves from the transmitters. This arrangementis suitable for long hole drilling but it is difficult to apply totunnel drilling because laser beams have to be detached from theirpositions for the duration of explosion so that they would not bedamaged. Further, if drilling equipments comprising more than one feedbeam are used, not even three laser beams are necessarily enough so thatthe direction and position of all feed beams could be measured by meansof them.

British Patent Application 2 180 117 discloses a method in which theposition of the measuring tip is determined by using three measuringunits mounted at fixed positions in the surroundings and two detectorsmounted to the shaft of the measuring tip, whereby each measuring unitmeasures the position and distance of the detector and on the basis ofthis the position of the measuring tip is calculated. This arrangementrequires that the measuring units are fixedly mounted in thesurroundings, wherefore this method cannot be applied as such to rockdrilling, nor can the arrangement disclosed in said Finnish PatentApplication.

The object of this invention is to achieve such a method for measuringthe position of a tool of a rock drill of a rock drilling equipment thatcan be used effectively and easily in all drilling and also when usingmore rock drilling equipments, if required.

The method of the invention is characterized in that the position of thetool relative to the base is determined by measuring, using at leastthree measuring devices situated at a known position relative to thebase and at a distance from one another, wherein at least two areattached to the base, and at least one measuring device is located at aknown position relative to the tool. At least some of the measuringdevices comprise a transmitter for transmitting oscilllation energy andcorrespondingly, at least some of the measuring devices comprise areceiver for receiving oscilllation energy. The distance between thetransmitters and receivers is measured on the basis of the oscilllationenergy transmitted by each transmitter; the distances between thereceivers and transmitters are calculated on the basis of the measureddistances; and the position of the tool relative to the base isdetermined on the basis of the distances calculated.

The essential idea of the invention is that at least two measuringdevices, that is, transmitters or receivers, mounted in the base of therock drilling equipment are used and similarly, receivers ortransmitters arranged at a known position relative to each rock drillor, when desired, in both cases transmitter-receivers, whereby theposition of the rock drills and their tools can always be determinedrelative to the base. A further essential idea of the invention is thatthe position of the base of the rock drilling equipment relative to therock in the general system of coordination is determined in some mannerknown per se, such as by means of laser or fixed point navigation,whereby when determining the position of the rock drill relative to thebase, they are at the same time determined relative to the generalsystem of coordination. According to one preferred embodiment of theinvention, a separate transmitter-receiver unit, for example, can beused to help in determining the position of the rock drills. Thetransmitter-receiver unit is placed at a suitable position in thevicinity of the rock to be drilled, such as below rock drills or boomsafter which the position of this separate transmitter-receiver unit isdetermined by means of measuring devices fixedly mounted in the baseafter which the separate unit can be used for measuring the position ofthe rock drills.

A logical and readily useable measurement is achieved with the methodaccording to the invention at the same time as a reliable measurement isobtained in all conditions by using several different measuring devices.

The invention will be explained in more detail in the accompanyingdrawing which illustrates schematically the application of the equipmentof the invention in connection with a rock drilling equipment providedwith three booms and three feed beams. In this patent application and inthe claims, a rock drilling equipment refers not only to an ordinaryrock drilling equipment provided with a drill rod, but also topercussion hammers provided with a striking tool or other such rockdrilling equipments intended for rock breakage or for making a hole.

In the FIGURE there is a base 1 of a rock drilling equipment to whichare connected pivotally in a manner known per se three booms 2a to 2cand to the ends of the booms 2a to 2c feed beams 3a to 3c, respectively.A rock drill 4a to 4c moves on each feed beam in its longitudinaldirection in a manner known per se and in the FIGURE a tool 5a to 5c isconnected to each rock drill which in the case shown in the FIGURE is adrill rod with which a hole is drilled. The joints between the booms 2ato 2c and feed beams 3a to 3c and the base 1, respectively and therotating of the booms and the feed beams relative to the joints aregenerally well known per se, wherefore they will not be explained anyfurther herein.

Three measuring devices 6a to 6c are attached to the base 1 of the rockdrilling equipment in a fixed position relative to the base. Themeasuring devices are connected to a control unit 7. Further, a separatemeasuring unit 8 is connected by way of example to the control unit 7.The measuring unit can operate in the same way as the fixed measuringdevices 6a to 6c. Measuring devices 9a to 9c and 10a to 10c of the feedbeam are further mounted in each feed beam 3a to 3c at certain positionsin each feed beam. All the measuring devices 6a to 6c, 8, 9a to 9c and10a to 10c can all be either transmitters, receivers ortransmitter-receivers. However, either all the measuring devices 9a to9c and 10a to 10c in the feed beam or, alternatively, the fixedmeasuring devices in the base 1 can be only transmitters and the othersreceivers, respectively. When using the separate measuring unit 8, itshould most practically be preferably of the transmitter-receiver type.

The operation of the method according to the invention starts in thatthe base 1 of the rock drilling equipment is driven to the drilling siteand its position in the general system of coordination relative to therock is determined in some manner known per se, such as by using lasermeasuring or fixed point measuring or any automatic measuring methodknown per se. In this patent application and in the claims thedefinition position refers to the location of said object and similarly,the direction of the longitudinal axis associated with a certain objectin the system of coordination in question. When the position of the base1 relative to the general system of coordination of the rock has beendetermined, the position of each feed beam 3a to 3c can be determined inthe general system of coordination by determining it first by means ofthe measuring devices 6a to 6c, 8, 9a to 9c and 10a to 10c relative tothe base and by means of information indicating the position of the baseconverting this mathematically into the position of each feed beam inthe general system of coordination. In practice, this occurs in thesimplest way for example so that the measuring devices 9a to 9c and 10ato 10c of the feed beam in the feed beams 3a to 3c are transmitters thattransmit a certain kind of oscilllation energy, that is, a measuringsignal. The signals transmitted by the measuring devices of each feedbeam 3a to 3c are measured separately and the control unit 7 calculateson the basis of their propagation time or the like the distances anddirections of each measuring device in the base to a correspondingmeasuring device after which, on the basis of this information, theposition of the feed beam can be calculated and thus also the positionof the feed beam. This calculation can be performed for one feed beam ata time at suitable intervals, for example. In that case in continuousmeasuring, signals transmitted by the measuring devices 9a and 10a ofthe feed beam 3a are measured for a moment, then signals transmitted bythe measuring devices 9b and 10b of the feed beam 3b are measured andfurther signals transmitted by the measuring devices 9c and 10c of thefeed beam 3c and it thus continues in a specific order, whereby thepositions of the feed beams are always known and the drilling or thedirection of the booms and the feed beams can be controlledcontinuously. The FIGURE shows schematically by broken lines for thesake of illustration only some of the possible measuring directionsbetween the different measuring devices.

If for some reason a measuring device of the feed beam should not beable to transmit reliably a signal relative to some measuring device ofthe base, one or more separate measuring units 8 can also be used whichis placed in a suitable position under the booms on the ground, forexample, and after that, by using the transmitter in the measuring unit8, the position of the measuring unit 8 relative to the base is measuredwith the fixed measuring devices 6a to 6c of the base. After this, thereceiver in the measuring unit 8 can be used for measuring the signalstransmitted by the measuring devices 9a to 9c and 10a to 10c of the feedbeams 3a to 3c because the position of the measuring unit is determinedin the system of coordination of the base and thus through the base 1 inthe general system of coordination of the rock. When desired, the fixedmeasuring devices 6a to 6c in the base 1 can naturally be replaced bytransmitters and use receiverrs as measuring devices 9a to 9c and 10a to10c in the feed beams. Further, all the measuring devices can also betransmitter-receiver detectors, whereby various verifying measurementsbetween the feed beams relative to one another, for example, canpossibly be accomplished in different ways. A plurality of separatemeasuring units 8 can be used if it is considered necessary due to thedrilling conditions.

Different oscillation waves can be used as measuring signals, wherebye.g. ultra sound or radio frequency electromagnetic vibration is useful.Either a certain kind of a pure signal or various noise signals can beused as signals, whereby the measuring reliability and accuracy can beconfirmed in different conditions in as suitable a way as possible.

The invention is above in the specification and in the drawing disclosedonly by way of example and it is in no way intended to be restrictedthereto. As a measuring device can be used two measuring devicesattached to the base 1 and one other measuring device the position ofwhich relative to the base 1 is known or can be measured. Further, themeasuring devices can be attached directly to the rock drill or itsbase, such as to its drill carriage or when using percussion hammers, toa mounting connected to the end of the boom. When using only onemeasuring device determined for place relative to the rock drill, thedirectional angles of the rock drill relative to the rock can in a knownsystem of coordination be measured by using e.g. gravity-based sensorsindicating the angle of inclination and sensors measuring the sidedeflection angles of the boom the angle information of which beingcombined by calculating the position of the measuring device determinesunambiguously both the position of the rock drill and the position ofthe tool connected to the rock drill relative to the rock in thedetermined system of coordination. Further, when using rock drillingequipments provided with a feed beam, the measuring devices can beattached, as mentioned in the specification, directly to the feed beamor, for example, to a separate cradle situated between the feed beam andthe boom relative to which the feed beam can move in the longitudinaldirection. In that case, as otherwise in arrangements provided with afeed beam, the position of the rock drill and the tool related theretois measured with a movement sensor or the like so that the position ofthe drill in the longitudinal direction of the feed beam is known andsimilarly, the position of the drill rod or other tool in the crossdirection of the feed beam is already predetermined and on the basis ofthis information the position of the tool can be determined relative tothe feed beam. Correspondingly, the longitudinal movement of the feedbeam relative to the cradle and its position in the cross direction ofthe axis of the tool and thus in the cross direction of the feed beamare previously known, whereby on the basis of this information, theposition of the tool can be calculated relative to the cradle andfurther, that way the position of the tool thorough the measuringdevices relative to the rock in a fixed system of coordination. Themethod can also be applied for following and predicting the movement ofthe rock drilling equipment so that the position of a certain measuringdevice is measured essentially continuously, whereby by means ofsuccessive points of location of a certain measuring device the movementof the measuring point and the direction of the movement or its changesrelative to both velocity and acceleration can be calculated.Correspondingly, by using other information, such as informationprovided by a second measuring device connected to the same boom orsensors indicating the angle of inclination, the position and themovement of the tip of the tool of the rock drill, for example, can bedetermined all the time when moving it, whereby the information aboutthe direction and position can be predicted, when desired, and slow downor otherwise control said movement in a manner appropriate for theresult.

I claim:
 1. A method for determining the position of a tool of a rockdrill relative to rock in a system of coordination when using rockdrilling equipment comprising a base, at least one drilling boompivotally mounted at one end to the base and a rock drill connectedpivotally relative to the boom at the other end of the boom and providedwith a tool, in which method the position of the base of the rockdrilling equipment in said system of coordination is determined and theposition of the tool in said system of coordination is determined on thebasis of the position of the base, the method comprising measuring theposition of the tool relative to the base using at least three measuringdevices situated at a known position relative to the base and at adistance from one another, wherein at least two of said measuringdevices are attached to the base, and at least one additional measuringdevice is located at a known position relative to the tool of the rockdrill, and wherein at least some of the measuring devices comprise atransmitter for transmitting oscillation energy and correspondingly, atleast some of the measuring devices comprise a receiver for receivingoscillation energy; measuring the distance between the transmitters andreceivers on the basis of the oscillation energy transmitted by eachtransmitter; calculating the distances between the receivers andtransmitters on the basis of the measured distances; and determining theposition of the tool relative to the base on the basis of the calculateddistances.
 2. A method according to claim 1, wherein said at least threemeasuring devices are attached to the base.
 3. A method according toclaim 1, including at least one additional separate measuring unit whichcomprises a transmitter and/or receiver and which is placed at adistance from the base of the rock drilling equipment; wherein theposition of the separate measuring unit relative to the base isdetermined by measuring the distances between the measuring unit andother transmitters and/or receivers on the basis of the oscillationenergy transmitted by the transmitters; and further wherein the separatemeasuring unit is used after determining its position along with themeasuring devices attached to the base for measuring the position of thetool.
 4. A method according to claim 1, wherein said at least twomeasuring devices are situated at a distance from one another and in aknown position relative to the rock drill; and wherein the position ofthe rock drill is determined by measuring the position of both of saidtwo measuring devices relative to the base, and by calculating theposition of the tool of the rock drill relative to the base on the basisof the sites of said two measuring devices.
 5. A method according toclaim 4 in which method the position of a drill rod relative to the baseis measured, the drill rod being used as the tool of the rock drillwhich is provided with a feed beam and moves along the feed beam whereinthe position of the feed beam is determined relative to the base by saidtwo measuring devices; and wherein the position of the drill rod isdetermined by taking into consideration its position in the crossdirection of the feed beam and its longitudinal position in thelongitudinal direction of the feed beam.
 6. A method according to claim1, wherein at least two rock drills are provided, and wherein twomeasuring devices are used for each rock drill, the position of said twomeasuring devices relative to the rock drill being known; and furtherwherein deflection angles of the tool of the rock drill relative to therock in a known system of coordination are determined with gravity-basedsensors indicating the angle of inclination.
 7. A method according toclaim 6 for determining the positions of the tools of the rock drills ofrock drilling equipment comprise at least two booms, wherein saidmeasuring devices in a known position relative to each rock drillcomprise both a transmitter and a receiver; and wherein the mutualposition of the rock drills is determined by measuring the distancesbetween said measuring devices on the basis of oscillation energy.
 8. Amethod according to claim 1, wherein, for measuring the distance, thepropagation time of the oscillation energy is measured between thetransmitter that transmitted said energy and a measuring device that isprovided with a receiver and that received said oscillation energy.